Allow file types to be associated with the rootfs.

This is now possible due to the kernel change to support
setting security contexts on rootfs inodes.

Change-Id: I2a9aac1508eceabb92c3ae8eb5c63a16b28dda6f
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

file.te

@@ -110,4 +110,5 @@ allow fs_type self:filesystem associate;
 allow sysfs_type sysfs:filesystem associate;
 allow file_type labeledfs:filesystem associate;
 allow file_type tmpfs:filesystem associate;
+allow file_type rootfs:filesystem associate;
 allow dev_type tmpfs:filesystem associate;